Mechanical recycling of consumer electronic scrap

Abstract: Consumer electronic equipment (brown goods), such as television sets, radio sets, and video recorders, are most common. However, recycling of consumer electronic scrap is only beginning. Characterization of TV scrap was carried out by using a variety of methods, such as chemical analysis, particle size and shape analysis, liberation degree analysis, thermogravimetric analysis, sink-float test, and IR spectrometer. A comparison of TV scrap, personal computer scrap, and printed circuit boards scrap shows that the content of non-ferrous metals and precious metals in TV scrap is much lower than in personal computer scrap or printed circuit boards scrap. It is expected that recycling of TV scrap will not be cost- effective by utilizing conventional manual disassembly. The result of particle shape analysis indicates that the non-ferrous metals particles in TV scrap formed as a variety of shapes, it is much more heterogeneous than for plastics and printed circuit boards. The results of sink-float tests demonstrate that a high recovery of copper could be obtained by an effective gravity separation process. Identification of plastics shows that the major plastic in TV scrap is high impact polystyrene. Gravity separation of plastics may encounter some challenges in separation of plastics from TV scrap because of specific density variations. Furthermore, Mechanical recycling of TV scrap oriented to recovery of non- ferrous metals is highlighted by utilizing several techniques, such as air table, eddy current separation, and optical sorting. The separation results reveal that air table separation is an effective technology to recover metals from consumer electronic scraps. By using a DGS table, approximately 90% of non-ferrous metals were recovered in the heavy product with a purity of 40%. Printed circuit boards and cables in TV scrap cause metals loss due to the fact that metals in printed circuit boards and cables are not liberated from plastics and ceramic materials. The study shows that eddy current separation and optical (metal) sorting process provide alternatives to recover metals from TV scraps. At last, new developments of eddy current separation, such as wet eddy current separation and Magnus separation are discussed in the thesis. A comparison of eddy current separation and Magnus separation on aluminum recovery shows that wet eddy current separation is more effective for recovery of fine non-ferrous particles.